Web Handling System

ABSTRACT

A web handling system is described, including a plurality of web handling controllers and a web handling process logic controller networked to form a ring network. A processor of the web handling process logic controller being configured to determine whether a fault exists within the ring network, and responsive to determining that a fault exists within the ring network, to generate and send signals throughout the ring network to switch the configuration of the ring network to at least one linear network.

INCORPORATION BY REFERENCE

The present patent application claims priority to, and incorporates byreference the provisional patent application identified by U.S. Ser. No.62/369,982, filed on Aug. 2, 2016.

BACKGROUND

Pneumatic, photoelectric, and ultrasonic systems have been used forguiding material webs by edge detection or line detection. Photoelectricbased systems, for example using optical sensors or infrared sensors,have been used to guide material webs based on features of the materialweb, such as an edge, an aspect of a material web at a given point onthe material, or a printed graphic running longitudinally along thematerial web. Most sensors detect the web or its features bytransmitting a signal and comparing a received signal through openatmosphere in relation to a received signal which has been passedthrough or interrupted by a web.

C shape sensors are common in web edge detection where the web passesthrough a gap in the C shape. Sensors are often housed in arms of the Cextending at least partially across the web. The sensors may be dividedbetween transmitter and receiver elements. The gap of the C shapesensors extend between the arms and may limit acceptable deviations inthe web plane of the traveling web while passing through the C shapesensor. In order to overcome this limitation, C shape sensors may bemounted on or connected to an articulable element, known as a movingsensor guide that allows the C shape sensors to move in response tochanges in the width of the material web. In addition, rollers may beemployed, such as fixed support bars, close to the C shape sensorsenabling better control over the web plane and enabling use of C shapesensors using smaller gaps. A plurality of C shape sensors have beenused to guide a single material web, with sensors on either side of thematerial web, to simultaneously perform edge detection on opposing edgesof the material web.

C shape sensors may be used in ultrasonic guiding systems, for exampleas described in U.S. Pat. No. 7,415,881. C shape sensors are also usedin photoelectric systems as described in U.S. Pat. No. 4,291,825 thatuses infrared sensing devices to perform web edge sensing to guide thematerial web.

Line sensors may be used which scan graphical patterns on the web,without performing edge detection, for guiding the material web. Linesensors may capture images and guide the material web based on acomparison of the images and the location of the graphical patterns witha stored set point. Line sensors may have a horizontal field of viewthat spans a portion or the entirety of the material web betweenopposing edges. However, the line sensors have a field of view in theweb direction of travel that is limited to one pixel and encompasses nomore than 5-7 microns of the web in the web direction of travel. Othersensors used in web guiding may include laser curtain sensors, raggededge sensors, fiber optics sensors, raised feature sensors, capacitanceor inductance sensors, and mechanical paddle or finger sensors.

Visual inspection systems for providing quality assurance to moving websof material currently exist. One visual inspection system is sold underthe trademark InPrint™ by Fife Corporation, the assignee of the presentpatent application. This visual inspection system provides qualityassurance by allowing direct, live image viewing of a moving web. Inparticular, this visual inspection system captures images of a movingweb at 10 images/second and compares the captured images to a referenceimage of the web to detect deviations of the captured image from thereference image. When deviations are detected, the visual inspectionsystem sounds an alarm, and/or directs a particular product to anappropriate location to be manually inspected.

Web handling systems include tension control components that are used tocontrol the tension in a web of material. The tension in the web isdetected by a load cell bearing sensor on the web of material, and thetension is controlled by a brake or clutch system that can vary the rateof movement of a roller for feeding and/or retrieving of the web ofmaterial. The tension control components also include a controller toreceive information indicative of the tension in the web of materialfrom the load cell bearing sensor and generate control signals that aretransmitted to the brake or clutch system to control the tension in theweb. Other tension control components include load cells, loadcell-based tension controllers, tension readouts, dancer controllers,magnetic particle clutches and brakes, and permanent magnet brakes andclutches.

In certain applications, web handling systems also include systems forphysically modifying or manipulating the web of material. These types ofweb handling systems include slitting systems used for cutting the webof materials along the web's longitudinal axis, and bowed rolls orspreader rolls used for separating parts of the web of material. Otherslitting products include electronic and pneumatic knifeholders, slitterpositioning systems, fully automated shear slitting systems, andmechanically linked slitting systems.

In certain applications, web handling systems also include windingproducts including core shafts, air shafts, expansion shafts, web shaftsand core holders, pneumatic brakes, safety chucks, core chucks,shaftless chucks and crushed core restorers.

Various web handling systems can be combined into one or more processline used for guiding, tensioning, slitting, and inspecting one or morewebs of material to make predetermined products, such as diapers. Theseweb handling systems have multiple controllers and sensors that areinterconnected via a star network topology.

BRIEF DESCRIPTION OF DRAWINGS

Certain embodiments of the present inventive concepts will hereafter bedescribed with reference to the accompanying drawings, wherein likereference numerals denote like elements, and:

FIG. 1 is an embodiment of a web handling system in accordance with thepresent disclosure;

FIG. 2 is a schematic view of a web handling process logic controllernetworked with a plurality of web handling controllers in accordancewith the present disclosure;

FIG. 3 is a schematic view of the web handling process logic controllernetworked with the plurality of web handling controllers in which afault is being detected in the web handling controller 24-3 inaccordance with the present disclosure;

FIG. 4 is a schematic view of an exemplary web handling controllerconstructed in accordance with the present disclosure; and

FIG. 5 is a schematic view of an exemplary web handling process logiccontroller constructed in accordance with the present disclosure.

FIG. 6 is a timing diagram illustrating an exemplary sequence of eventsutilized in synchronizing slave clocks with a master clock in accordancewith the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Specific embodiments of the present disclosure will now be described indetail with reference to the accompanying drawings. Further, in thefollowing detailed description of embodiments of the present disclosure,numerous specific details are set forth in order to provide a morethorough understanding of the disclosure. However, it will be apparentto one of ordinary skill in the art that the embodiments disclosedherein may be practiced without these specific details. In otherinstances, well-known features have not been described in detail toavoid unnecessarily complicating the description.

Unless expressly stated to the contrary, “or” refers to an inclusive orand not to an exclusive or. For example, a condition A or B is satisfiedby anyone of the following: A is true (or present) and B is false (ornot present), A is false (or not present) and B is true (or present),and both A and B are true (or present).

In addition, use of the “a” or “an” are employed to describe elementsand components of the embodiments herein. This is done merely forconvenience and to give a general sense of the inventive concept. Thisdescription should be read to include one or at least one and thesingular also includes the plural unless it is obvious that it is meantotherwise.

Finally, as used herein any reference to “one embodiment” or “anembodiment” means that a particular element, feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. The appearances of the phrase “in oneembodiment” in various places in the specification are not necessarilyall referring to the same embodiment.

The terminology and phraseology used herein is for descriptive purposesand should not be construed as limiting in scope. Language such as“including,” “comprising,” “having,” “containing,” or “involving,” andvariations thereof, is intended to be broad and encompass the subjectmatter listed thereafter, equivalents, and additional subject matter notrecited.

The prior art web handling systems can be improved by providing betternetworking solutions, and time-based synchronization of the controllersand sensors. It is to such an improved web handling system that thepresent disclosure is directed.

Referring now to the figures, shown in FIG. 1 is a web handling system10 for handling a continuous material web 12. The continuous materialweb 12 is passed over a variety of rollers 13 in accordance with thepresent disclosure. The rollers 13 may include cylinderically shaped webrollers or other types of rollers, including, but not limited to heattransfer rollers, idler rollers, vacuum rollers, bowed rollers andspreader rollers. The web handling system 10 may be used in web guiding,tension control, and quality inspection industries, for example. The webhandling system 10 includes, by way of example, one or more web guidingsystems 14, one or more supply roller 15, one or more tension controlsystems 16, one or more windup roller 17, one or more slitting systems18 and one or more video web inspection systems 20 synchronized by a webhandling process logic controller 22. Each of the web guiding systems14, tension control systems 16, slitting systems 18, video webinspection systems 20 has a web handling controller 24 (shown by way ofexample as 24-1, 24-2, 24-3 and 24-4) in FIGS. 2 and 3 that will bediscussed in more detail below. The web handling controllers 24 are alsonetworked with a web handling process logic controller 22. As shown inFIG. 4, the web handling controllers 24 are provided with a processor30, a clock 32 and at least two separate network communication ports 34a and 34 b. The processor 30 is coupled to the clock 32 and the at leasttwo separate network communication ports 34 a and 34 b. The processor 30receives clock signals from the clock 32 and may synchronize the clocksignals with a master clock, as discussed below. As shown in FIG. 5, theweb handling process logic controller 22 is also provided with aprocessor 40, a clock 42 and at least two separate network communicationports 44 (that are designated in FIG. 4 with the reference numerals 44 aand 44 b). The processor 40 is coupled to the clock 42 and the at leasttwo separate network communication ports 44 a and 44 b. The processor 40receives clock signals from the clock 42 and may transmit timing signalsthe the web handling controllers 24 such that the clock 42 becomes amaster clock for all of the web handling controllers 24 within thenetwork, as described below.

As will be described below, the processor 40 of the web handling processlogic controller 22 and the processors 30 of the web handlingcontrollers 24 are programmed or hardware configured to communicateusing a ring-network topology having the ability to detect a fault inthe network, and to automatically switch from a network using a ringtopology to two separate linear topological networks. Once the webhandling process logic controller 22 and the web handling controllers 24switch to the linear topological networks, the web handling processlogic controller 22 sends out a series of neighbor check requests fromthe communication ports 44 a and 44 b to cause each of the web handlingcontrollers 24 to check to see if the web handling controllers 24 cancommunicate with its neighbors in the linear topological networks. Thischeck can be accomplished by the web handling controllers 24 pollingneighboring web handling controllers 24 and then reporting back to theweb handling process logic controller 22. Utilizing a ring topology thatcan switch to two separate linear topological networks provides the webhandling system 10 with enhanced communication reliability andredundancy as compared to the prior art web handling systems thatutilize a star network topology.

For example, as shown in FIGS. 2 and 3, the web handling controller 24-1polls the web handling controller 24-2; the web handling controller 24-2polls the web handling controller 24-3; and the web handling controller24-3 polls the web handling controller 24-4. Likewise, the web handlingcontroller 24-4 receives the neighbor check request and then polls theweb handling controller 24-3; the web handling controller 24-3 polls theweb handling controller 24-2; and the web handling controller 24-2 pollsthe web handling controller 24-1. In this manner, at some point withinthe network two of the web handling controllers 24-1-24-4 will notreceive a neighbor check response due to a fault in the network. Bypolling neighboring web handling controllers 24, the web handlingprocess logic controller 22 determines a location of the fault in thenetwork, and also determines the identity of the web handlingcontrollers 24 on each of the linear topology networks. For example, asshown in FIG. 3, a fault exists between the communication port 34 a ofthe web handling controller 24-4, and the communication port 34 b of theweb handling controller 24-3. In this example, the web handling processlogic controller determines the location of the fault, due to the webhandling controller 24-4 transmitting a request and not receiving aneighbor check response.

In one embodiment, the web handling process logic controller 22 and theweb handling controllers 24 utilizing a device level ring protocol andan ethernet networking protocol to communicate. In this embodiment, thedevice level ring protocol provides high network availability in a ringtopology for the web handling process logic controller 22 and the webhandling controllers 24. In this embodiment, the communication ports 34a, 34 b, 44 a and 44 b are Ethernet ports with embedded switchtechnology. The device level ring protocol provides fast network faultdetection and reconfiguration in order to support the most demanding webhandling control applications.

In one embodiment, the device level ring protocol operates at Layer 2(in the ISO OSI network model). Thus, the presence of the ring topologyand the operation of the device level ring protocol are transparent tohigher layer protocols such as TCP/IP and CIP, with the exception of adevice level ring Object that provides a device level ring configurationand diagnostic interface via CIP.

In one embodiment, the processor 40 of the web handling process logiccontroller 22 is programmed with a ring supervisor that monitors trafficon the communication ports 44 a and 44 b. The ring supervisor cancontrol the traffic on the communication ports 44 a and 44 b toselectively prevent packets from circulating within the network, as wellas to send beacon frames and/or announce frames.

Beacon frames can be sent from both of the web handling process logiccontroller 22 communication ports 44 a and 44 b to detect cable breaksand/or malfunctions of any one of the web handling controllers 24. Thebeacon frames can also carry precedence values so that an actingsupervisor can be determined on a network with multiple ringsupervisors. In one embodiment, by default, Beacon frames are sent outat an interval of 400 μs and during ring state change.

Announce frames are sent from the unblocked port at a predeterminedinterval, such as once per second, and during ring state change. Theannounce frames may transmit instructions about topologyreconfigurations.

In some embodiments, each of the web handling process logic controller22 and the web handling controllers 24 have a unique address, such as aMAC address. When the web handling process logic controller 22 receivesa packet on one of the communication ports 44 a or 44 b, e.g., thecommunication port 44 a, the web handling process logic controller 22determines whether the packet needs to be received and interpreted byitself (e.g., the packet has the web handling process logic controller'sMAC address) or whether the packet should be forwarded via the othercommunication port 44 a or 44 b, e.g., the communication port 44 b.Likewise, when the web handling controller 24 receives a packet on oneof the communication ports 34 a or 34 b, e.g., the communication port 34a, the web handling controller 24 determines whether the packet needs tobe received and interpreted by itself (e.g., the packet has the webhandling process logic controller's MAC address) or whether the packetshould be forwarded via the other communication port 34 a or 34 b, e.g.,the communication port 34 b.

The active ring supervisor running on the processor 40, blocks trafficon one of the communication ports 44 a and 44 b with the exception offew special frames and does not forward traffic from one communicationport 44 a to 44 b to the other communication port 44 a to 44 b. Becauseof this configuration a network loop is avoided and only one path existsbetween any two of the web handling process logic controller 22 or theweb handling controllers 24 during normal operation. In someembodiments, the web handling process logic controller 22 is always theactive ring supervisor and transmits a beacon frame through bothcommunication ports 44 a and 44 b at a predetermined interval or randominterval, such as 400 μs.

For most implementations, beacon-based device level ring is preferreddue to faster fault detection and recovery times. The active ringsupervisor also sends announce frames at a predetermined or randominterval, such as once per second.

The beacon and announce frames serve several purposes. First, thepresence of beacon and announce frames inform the web handlingcontrollers 24 to transition from linear topology mode to ring topologymode and vice versa. Second, a loss of beacon frames at the web handlingprocess logic controller 22 enables detection of certain types of ringfaults. (Note that the web handling controllers 24 are also able todetect and signal ring faults). Third, in some embodiments, the beaconframes carry a precedence value, allowing selection of an activesupervisor when multiple ring supervisors are configured.

The web handling process logic controller 22 and the web handlingcontrollers 24 can also be configured to synchronize clocks 32 and 42using any suitable protocol, such as a protocol known as precision timeprotocol. Suitable versions of precision time protocols are described inIEEE 1588-2002 and 1588-2008.

Precision time protocol described in IEEE 1588-2002 and 1588-2008 uses ahierarchical master-slave architecture for clock distribution. Under theprecision time protocol architecture, a time distribution systemconsists of one or more communication media (network segments), and oneor more clocks, such as the clocks 32 and 42. An ordinary clock is adevice with a single network connection and is either the source of(master) or destination for (slave) a synchronization reference. Aboundary clock has multiple network connections and can accuratelysynchronize one network segment to another. A synchronization master isselected for each of the network segments in the system. The root timingreference is called the grandmaster. The grandmaster transmitssynchronization information to the clocks residing on its networksegment. The boundary clocks with a presence on that segment then relayaccurate time to the other segments to which they are also connected.

A simplified PTP system frequently consists of ordinary clocks connectedto a single network, and no boundary clocks are used. A grandmaster iselected and all other clocks synchronize directly to it.

IEEE 1588-2008 introduces a clock associated with network equipment usedto convey PTP messages. The transparent clock modifies PTP messages asthey pass through the web handling process logic controller 22, and/orone of the web handling controllers 24. Timestamps in the messages arecorrected for time spent traversing the network equipment. This schemeimproves distribution accuracy by compensating for delivery variabilityacross the network.

PTP typically uses the same epoch as Unix time (Midnight, 1 Jan. 1970).While the Unix time is based on Coordinated Universal Time (UTC) and issubject to leap seconds, in some embodiments PTP is based onInternational Atomic Time (TAI) that moves forward monotonically. ThePTP grandmaster communicates the current offset between UTC and TAI, sothat UTC can be computed from the received PTP time.

Synchronizing the clocks, such as by using PTP, in web handling(guiding, tension control, slitter positioning etc.) applicationsprovides the mechanism to synchronize the web handling controllers 24across the network. This is important from a guiding and web handlingperspective as this allows sensor signals (such as the position ortension of the web of material) to be collected or generated from anyweb handling controller 24 to be broadcast on the network and sharedamong specific or all web handling controllers 24.

Each web handling controller 24 provides one or more independent closedloop control systems. The nature of closed loop control systems dictatethat phase jitter of the sensor signals used as inputs to the controlloop be minimized or eliminated. In the presently disclosed web handlingcontrollers 24, very precise timing via any suitable logic, such as FPGAlogic, may be used to collect analog signals cyclically at consistentmoments in time to prevent signal phase deviations and jitter. Controlloop calculations performed in software are also synchronized to thesame sampling process by virtue of high priority CPU interruptmechanisms so calculations are done with the most recent data available.This provides control signals generated at precise cyclical moments tomaximize the web controller stability and correction speed.

The timing logic inside each web handling controller 24 also containsadditional capability to generate and accept signals to synchronize thepreviously described cyclic signal sampling process of the web handlingcontrollers 24 across the network, thus providing the basis for sharedguiding signals between units with signals that remain in phase andcontain minimum jitter. By maintaining the same signal timing integrityacross the network, control loops running in any connected web handlingcontroller 24 can use remote sensor data as if the remote sensor datawere collected locally without penalizing control loop performance.

The timing logic, using precision time protocol for example, results inclock synchronization. Because the clocks of the web handlingcontrollers 24 in the network are precisely synchronized, the closedloop control process previously described is also synchronized.Synchronization implies that a single clock source must become themaster to which all other web handling controllers 24 seek to mirror.Again the precision time protocol, for example, provides the means toaccomplish this by the precision time protocol's use of an arbitrationsystem to determine which device (e.g., the web handling process logiccontroller 22, or one of the web handling controllers 24 will be themaster. In order to work in harmony with existing precision timeprotocol mechanisms that may be present in any given network, the webhandling controllers 24 described herein may implement precision timeprotocol in such a way that they will not become precision time protocolmasters, however, in absence of other precision time protocol masters inthe network, the presently disclosed web handling controllers 24 willautomatically arbitrate a precision time protocol master when needed inorder to synchronize the control loops of the web handling controllers24.

Several mechanisms are at work inside the timing logic to accomplishsynchronization. The timing logic may have the capability to “snap”instantly to a clock value, which is often done when a device (e.g., theweb handling process logic controller 22, or the web handlingcontrollers 24) is first powered on with existing precision timeprotocol clocks already established. As the precision time protocolprocess runs on the processor 30 and the processor 40, for example, thepresently disclosed web handling controllers 24 may use a controlalgorithm fed by the amount of correction needed from each adjustmentmoment to actually tune the timing logic, e.g., FPGA clock frequency. Inthis embodiment, the clock 32 is a FPGA clock. This makes the clock 32of the web handling controller 24 seek the same frequency as the masterclock resulting in smaller adjustments. In some embodiments, thisprocess runs continuously on the processor 30 of the web handlingcontroller 24 to maintain synchronization.

FIG. 6 shows an exemplary method that may be run by the processor 30 ofthe web handling controller 24 to synchronize a slave clock to a masterclock in accordance with the present disclosure. In this example, anOffset and Network Propagation Delay used by processor 30 of the webhandling controllers 24 to synchronize the clock 32 with the clock 42can be calculated as follows:

Delay+Offset=t2−t1

Delay−Offset=t4−t3

Delay=(t2−t1)+(t4−t3))/2

Offset=((t2−t1)−(t4−t3))/2

In some embodiments, the processor 30 of one of the web handlingcontrollers 24, or the processor 40 of the web handling process logiccontroller 22 acting as a slave clock (referred to herein as the “slaveclock”) synchronizes the clock 32 or the clock 42 to the master clock ofthe network by using a bidirectional multicast communication as shown inFIG. 6. In some embodiments, the synchronization of the clock 32 or theclock 42 can be accomplished as follows. The processor 30 of the one ofthe web handling controller 24 or the processor 40 of the web handlingprocess logic controller 22 acting as the master clock (referred toherein as the “master clock”) issues a synchronization packet containinga timestamp of the time when the synchronization packet left the masterclock via one of the communication ports 34 a, 34 b, 44 a, or 44 b. Themaster clock may also, optionally, issue a follow-up packet containing atimestamp for the synchronization packet. The use of a separatefollow-up packet allows the master clock to accurately timestamp thesynchronization packet on networks where the departure time of a packetcannot be known accurately beforehand. For example, collision detectionand random backoff mechanisms of ethernet communication prevents theexact transmission time of a packet from being known until the packet iscompletely sent without a collision being detected, at which time it isimpossible to alter the packets content. A slave clock receives themaster clock synchronization packet and timestamps the packets arrivalusing the slave clock's own clock 32 or 42. The difference in thesynchronization packet's departure timestamp and the synchronizationpackets arrival timestamp is a combination of the slave clock's offsetfrom the master clock and the network propagation delay. By measuringand storing the offset and using the offset to adjust the slave clock bythe offset measured at this point, the offset between the master clockand the slave clock can be reduced to the network propagation delayonly.

In some embodiments, the processor 30 of the web handling controller 24or the processor 40 of the web handling process logic controller 22acting as the master clock operates under an assumption that the networkpropagation delay is symmetrical. That is, the delay of the packet sentfrom the master clock to a slave clock is the same as the delay of apacket sent from the slave clock to the master clock. By making thisassumption, the slave clock can discover and compensate for thepropagation delay. The slave clock accomplishes this by issuing arequest packet which is time stamped on departure from the slave clock.The request packet is received and timestamped by the master clock, andthe arrival timestamp is sent back to the slave clock in a delay packet.The difference in the two timestamps is the network propagation delay.

By sending and receiving the synchronization packets, the slave clockscan accurately measure the offset between the slave clock's clock 32 or42 and the master clock. The slave clocks can then adjust their clocksby this offset to match the time of the master clock.

The foregoing description provides illustration and description, but isnot intended to be exhaustive or to limit the inventive concepts to theprecise form disclosed. Modifications and variations are possible inlight of the above teachings or may be acquired from practice of themethodologies set forth in the present disclosure.

Also, certain portions of the implementations may have been described as“components” or “circuitry” that perform one or more functions. The term“component” or “circuitry” may include hardware, such as a processor, anapplication specific integrated circuit (ASIC), or a field programmablegate array (FPGA), or a combination of hardware and software.

Even though particular combinations of features are recited in theclaims and/or disclosed in the specification, these combinations are notintended to limit the disclosure. In fact, many of these features may becombined in ways not specifically recited in the claims and/or disclosedin the specification. Although each dependent claim listed below maydirectly depend on only one other claim, the disclosure includes eachdependent claim in combination with every other claim in the claim set.

No element, act, or instruction used in the present application shouldbe construed as critical or essential to the invention unless explicitlydescribed as such outside of the preferred embodiment. Further, thephrase “based on” is intended to mean “based, at least in part, on”unless explicitly stated otherwise.

What is claimed is:
 1. A web handling system comprising: a plurality ofweb handling controllers, each of the web handling controllers having aweb handling processor, a first communication port and a secondcommunication port; and a web handling process logic controller having aprocessor, a third communication port and a fourth communication port,the first communication port, the second communication port, the thirdcommunication port and the fourth communication port being connected toform a ring network, the processor of the web handling process logiccontroller being configured to determine whether a fault exists withinthe ring network, and responsive to determining that a fault existswithin the ring network, to generate and send signals throughout thering network to switch the configuration of the ring network to at leastone linear network.
 2. The web handling system of claim 1, wherein oneof the web handling controllers is a component of a web guiding system.3. The web handling system of claim 1, wherein one of the web handlingcontrollers is a component of a web tension control system.
 4. The webhandling system of claim 1, wherein one of the web handling controllersis a component of a video web inspection system.
 5. An apparatus,comprising: a web handling process logic controller having a processor,a first communication port and a second communication port, theprocessor configured to control the first communication port, and thesecond communication port to be a part of a ring network, the processorof the web handling process logic controller also being configured todetermine whether a fault exists within the ring network, and responsiveto determining that a fault exists within the ring network, to generateand send first signals via the first communication port and secondsignals via the second communication port, the first and second signalsincluding instructions to switch the configuration of the ring networkto at least one linear network.
 6. The apparatus of claim 5, wherein theprocessor is configured to be a ring supervisor that monitors traffic onthe first and second communication ports, the processor also controllingthe traffic on the first and second communication ports to selectivelyprevent packets from circulating within the ring network.
 7. Theapparatus of claim 6, wherein the processor is configured to be the onlyring supervisor within the ring network.
 8. A web handling systemcomprising: a plurality of web handling controllers, each of the webhandling controllers having a web handling processor, a first clock, afirst communication port and a second communication port; and a webhandling process logic controller having a processor, a second clock, athird communication port and a fourth communication port, the firstcommunication port, the second communication port, the thirdcommunication port and the fourth communication port being connected toform a network, the processor of the web handling process logiccontroller receiving a clock signal from at least one of the first clockand the second clock, and providing clock signals via the thirdcommunication port and the fourth communication port, the clock signalsincluding a clock reference and instructions configured to synchronizethe first clocks of the web handling controllers.
 9. The web handlingsystem of claim 1, wherein one of the web handling controllers is acomponent of a web guiding system.
 10. The web handling system of claim1, wherein one of the web handling controllers is a component of a webtension control system.
 11. The web handling system of claim 1, whereinone of the web handling controllers is a component of a video webinspection system.